This invention relates to a seat slide device for vehicles.
A seat slide device for vehicles which can adjust the position of a vehicle seat forwardly or rearwardly is disclosed, for example, in Japanese Laid-open Patent Publication Hei 7-304361 (1995) and is known. This seat slide device generally includes a lower rail having an approximately U-shaped cross section which is adapted to be fixedly secured to a vehicle floor, an upper rail having an approximately inverted T-shaped cross section which is slidably supported with respect to the lower rail and to which a seat cushion is fastened, and a locking lever which is rotatably supported on the upper rail and is engaged with or disengaged from the lower rail to allow a sliding motion of the upper rail with respect to the lower rail.
The lower rail of this conventional seat slide device is provided with the row of locking holes arranged along the longitudinal direction of the lower rail, while a plurality of locking teeth which are adapted to be fitted into some of the row of the locking holes are formed in the locking lever. Furthermore, an auxiliary plate in which the row of through holes are formed and extends in the longitudinal direction of the upper rail is fixedly mounted on the upper rail, wherein the row of the through holes are disposed close to the row of the locking holes and the locking teeth pass through the through holes.
In such a construction, upon rotation of the locking lever, the locking teeth of the locking lever pass through the row of through holes of the auxiliary plate and are fitted into the row of locking holes of the lower rail so that the locking lever is engaged with the lower rail and the slide movement of the upper rail relative to the lower rail is restricted (a locked state).
Furthermore, upon rotation of the locking lever in a reverse direction, the locking teeth of the locking lever are released from the row of locking holes of the lower rail and the row of through holes of the auxiliary plate so that the locking lever is disengaged from the lower rail and the slide movement of the upper rail relative to the lower rail becomes possible (an unlocked state).
Under the afore mentioned locked state, when a load is applied in the longitudinal direction of the rail due to a collision of the vehicle or the like, since the locking teeth of the locking lever are not only fitted into the row of the locking holes of the lower rail but also pass through the row of the through holes of the auxiliary plate disposed close to the locking teeth, this load is received as a shearing load and hence, a high locking strength is assured.
However, in such a conventional device, to assure the high locking strength, the auxiliary plate which is provided with the row of the through holes through which the locking teeth of the locking lever pass and which extends in the longitudinal direction of the rail becomes necessary, and furthermore, since the row of the through holes must be disposed close to the row of the locking holes, the auxiliary plate widens the width of the rail, increases the weight and raises the cost.
Accordingly, it is an object of the present invention to provide a seat slide lock device for vehicles which can assure a high locking strength without enlarging the width of a rail.
To achieve the above object of the present invention, there is provided a seat slide device including a first and second row of locking teeth which are formed on a lower rail along the longitudinal direction of the rail such that these rows of the locking teeth are disposed in an opposed manner while sandwiching a locking lever therebetween, a first flange portion which is formed on the locking lever opposed to the first row of the locking teeth and is provided with a plurality of locking holes into which some of the first row of the locking teeth are fitted, and a second flange portion which is formed on the locking lever opposed to the second row of the locking teeth and is capable of coming into contact with some of the second row of the locking teeth in a direction perpendicular to the longitudinal direction of rail.
According to such technical conception, upon rotation of the locking lever, the locking lever is engaged with the lower rail such that the first row of the locking teeth of the lower rail are fitted into the locking holes of the first flange portion of the locking lever and hence, the slide movement of the upper rail relative to the lower rail is restricted (a locked state). Here, the second flange portion of the locking lever comes into contact with the second row of the teeth of the lower rail perpendicular to the longitudinal direction of the rail.
Furthermore, upon rotation of the locking lever in a reverse direction, the first row of the locking teeth of the lower rail are released from the locking holes of the first flange portion of the locking lever so that the locking lever is disengaged from the lower rail and the slide movement of the upper rail relative to the lower rail becomes possible (an unlocked state).
In the above-mentioned locked condition, when the load is applied in the longitudinal direction of the rail due to a collision of vehicle or the like, in addition to the fitting engagement between the locking holes of the first flange portion of the locking lever and the first row of the locking teeth of the lower rail, the second flange portion of the locking lever comes into contact with the second row of the locking teeth of the lower rail and hence, this load is shared and supported in two rows in the longitudinal direction of the rail as a shearing load thus assuring the high locking strength.
Accordingly, the auxiliary plate which has been conventionally necessary is no longer necessary so that the high locking strength can be attained without increasing the width of the rail.
In a preferred construction, the second flange portion is provided with a plurality of through holes through which some of the second row of locking teeth pass and the front and rear walls of the through holes in the longitudinal direction of rail can be brought into contact with some of the second row of the locking teeth with a given gap or play.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.